Comp in control

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I am trying to do a comp in control move with a 3/4 inch cutter in a 1 inch hole. Is this possible? I have seen a Haas machining center do this. I have the 18i Fanuc control.

 

MX2 [email protected]

[YoDoug®]

It depends on how big your lead in move is. Our Fanuc 15mb will alarm if the comp offset value is greater than the g41/g42 on move.

 

You could always set MCX to output comp moves above the hole then plunge.

[ToolMan184]

Thats a good reason to use wear comp.

[Guest]

Control comp?

 

What's that? Isn't that something they used to use a looong time ago?

[Guest CNC Apps Guy 1]

Yeah, that's when they wrote programs by hand with calculators at the control.

 

That's REALLY a good reason to use wear comp. JM2C

[Smit]

The easy way is to pick the center of the hole as a point then chain the hole diameter. Check the use entry point in your lead in/lead out dialog box and remove any entry line length. Your center point will give you the entry line length you need. You can add a SMALL arc radius if you want to.

 

Your lead in must be more than the radius of the tool, I would typically use the tool radius plus .1, so .475. In your case I'd round it off to .5.

 

I'd agree with everybody else though, it is easier on the programmer if you use wear comp.

 

HTH

[PeterM]

For what you asked for use a lead in line perpendicular .42 ,arc .46 with 180 deg sweep. The tool will start at center. BTW wear is easier.

[#Rekd™]

Hi,

 

I would use circle mill, pick a point (not the chain) The cutter will enter in the center of the hole. Use wear so the operator can adjust hole size if required.

 

John

[Nathan G. Baldwin]

You might have to turn your look ahead off, and don't extend the start or end of the contour in your lead in/out

 

HTH

[Smit]

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You might have to turn your look ahead off,

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Also turn your optimize on, this will prevent the tool from gouging smaller radius corners. Not important to this particular case, but if you profile it will be.

[chris m]

WEAR WEAR WEAR

[G Caputo]

Why does everyone always bash the whole control comp thing? What is so difficult about putting in the actual diameter or radius in the control and using control comp? Whatever you want your lead in/lead out to be enter it in Mcam, enter it in the box and add the radius of your tool? If I call out a 1" em and it's been reground to .930", they throw .465" radius or a .930 diameter in the control and it runs fine.

 

Say a hot job comes rolling in here at 1 in the morning and has to be back to the customer at 7 am. Is the operator/machinist working midnights supposed to figure out all his coordinates and then subtract the cutter radius before entering them in the control before he runs his own program just so he can use wear? That sounds absurd.

 

I can see if your a 1 man shop or EVERYTHING gets programmed offline then that would work fine. But when you have people programming at the machine, and offline, cutter comp in the control is the easiest way to go. JM2C.

[William Grizwald]

"Why does everyone always bash the whole control comp thing?..."

 

Normally, I could care less...but, since I'm stuck in a shop now where we have hundreds (thousands?) of existing programs running on machines with fixed tool locations, I must continue the maddness of using radius comp.

 

First and foremost: I can have very short leadin-leadout moves using centerline (Wear). Second, If I'm driving planer contours where the tool happens to be the same radius as the contour, Mastercam sometimes barfs. Third, every other toolpath in your program has centerline if there is no comp - so why be different. Forth, many cam systems (MCX included) many times output short moves on exit if your not paying attention to the details. You'll get an alarm at the machine.

 

Regarding the simplicity of using dia or radius in the control. You can be just as clean and simple if you plan ahead by driving all internal corners with some radius. That way, any wear comp will be driven. MCX though may require additional geometry to be created. This would be simplified greatly if it had corner control with the option to drive a small radius on all internal corners.

 

--

Bill

[Smit]

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I can have very short leadin-leadout moves using centerline (Wear).

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You can do that with control comp too, just add the radius of the cutter to your short lead in line. If you want a .1 lead in just make it .6 with comp in control (with a 1" cutter-.35 with a .5" cutter). Same entry line length on the machine.

 

quote:

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Second, If I'm driving planer contours where the tool happens to be the same radius as the contour, Mastercam sometimes barfs.

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Turn off infinite look ahead and turn on optimization. No more barfs.

 

quote:

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Third, every other toolpath in your program has centerline if there is no comp - so why be different.

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I rarely programmed centerline when using comp in control. The machinists knew to add .01 to rough tools, or just add .01 to your toolpath.

 

There are things you have to keep in mind when using control comp, but if you do it all the time those things become automatic and are not a big deal.

 

I haven't programmed comp in control since version 9, (at least on a daily basis) but Mastercam did an excellent job of making it easier with the optimization feature. I would assume they haven't moved backwards in X2.

[Tinny]

quote:

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Control comp?

 

What's that? Isn't that something they used to use a looong time ago?

 

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Not that old chestnut again.

[Guest]

quote:

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Not that old chestnut again.

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Oh yeah forgot or still use it across the pond too

 

[Mgrenier]

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I would assume they haven't moved backwards in X2.

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You are right. We use it all the time here (company's decision)and I like it a lot. Makes the understanding of an NC program a lot easier for everybody...

[chris m]

Why do they need to "understand" the NC program? Are you writing books or making parts? I don't want or need my operators trying to "figure out what I'm doing" I need them to make parts and make them efficiently. They pay me a lot of money to get the programs right and have everything ready to go when the job gets to the machine. I rarely have a problem when an operator leaves .0015 worth of comp in his tool and forgets before changing out the 3/8 endmill in the last job for the 1/2 in the new one and running the first part of his next job; leaving .187 in there and changing to a 1/2 endmill, however....

 

The only plus to "blueprint" control comp is to allow the guy on the shop floor to "understand" and, most likely, f_ck with something that I have done in a specific way; ergo: comp in control s_cks for the business I happen to be in.

 

C

[Thee Dragracer1951]

Wear comp in my shop.

I catch someone messing with a program. I'm most likely gonna have a stern talking with them. Just to let them know that it ain't their shop. It's My shop. And I get to do it how I want to. Heck, I'll even tell them why I do it that way. But this ain't no democracy. They don't like it, they can go crash someone elses machines.

[rdshear]

quote:

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We use it all the time here (company's decision)and I like it a lot. Makes the understanding of an NC program a lot easier for everybody...

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I agree. The programs are much more readable.

 

quote:

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Why do they need to "understand" the NC program? Are you writing books or making parts?

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Both. Several of the people we have here running the machines are journeyman machinists that when the need comes up, hand program. (Hot job ect..) Therefore, they are very familliar with the programming of the machines and have done it by hand themselves for years. If the programs we send them aren't readable, they would waste time trying to figure out what we are doing or single blocking through to make sure it runs ok. We do not do production here and on individual unique parts, time on the job would suffer if the programs weren't readable. Control comp is what they are used to, control comp is what we send them. Life is simpler.

 

In an environment where the people running the programs never look at them and just hit the green button and walk away. Any kind of comp would probably work just as well.

 

Personally if I had to read through a program with wear comp it would take me more time to figure out what it is doing than with control because the numbers would not be what I see on the drawing.

 

I'm happy with control, you may be happy with wear, Can't we all just get along?

 

 

Rick

[doyleg]

We use control comp here. all we have here are "cnc machinists" - not operators. We do little production. our largest batches are in the 20 part range. we must be able to look at the pgm and see what it is doing and this is the easiest way for that to happen. However, if we were doing nothing but production. i'd have to go with wear comp. because all of your tooling had better be set-up prior to running the job and should already have all of your offsets to be put into the machine and your program would more than likely already have been proven out by someone qualified.

 

Apples and oranges.

[Guest]

No to nit pick, but "ANY" CNC "machinist" worth his salt should be able to read the code, control or wear.

[doyleg]

yes but this is quicker and easier for everyone. no need to get calculators and such. you can just read it off the screen.

[Thee Dragracer1951]

You know, this is a Ford Chevy thing. I'm not going to convince anyone outside of the choir the virtues of wear comp and the evils of control comp.

But, I do both prototyoe and production at my shop. I can fix a problem in the file faster in Mastercam than I can in the control. and then I have the change for next time. Also...I have ZERO chance of finger fumbleing the number in the control.

But you already knew that.

[within a thou]

I personally use wear for my comp I find when you use control comp and your D value is half of your cutter you run into countless problems in your g41 lead in move has to be greater then the rad of your tool which forces you to start farther away from the part. I dunno who you guys are doing work for but I haven;t come across anyone who will pay me for cut air so I am going to stick with wear comp and kep my tool cutting steel